Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Compact total irradiance monitor: Flight demonstration



Dave Harber, John H. Lehman, Nathan A. Tomlin, Christopher S. Yung, Malcolm G. White, Zach Castleman, Ginger Drake, Samuel Van Dreser, Nat Farber, Karl Heurman, Joel Rutkowski, Alan Sims, Jacob Sprunck, Cameron Straatsma, Isaac Wanamaker, Wengang Zheng, Greg Kopp, P. Pilewskie, Michelle S. Stephens


The long-term balance between Earth’s absorption of solar energy and emission of radiation to space is a fundamental climate measurement. Total solar irradiance (TSI) has been measured from space, uninterrupted, for the past 40 years via a series of instruments. The Compact Total Irradiance Monitor (CTIM) is a CubeSat instrument that will demonstrate next-generation technology for monitoring total solar irradiance. It includes novel silicon-substrate room temperature vertically aligned carbon nanotube (VACNT) bolometers. The CTIM, an eight-channel 6U CubeSat instrument, is being built for a target launch date in late 2020. The basic design is similar to the SORCE, TCTE and TSIS Total Irradiance Monitors (TIM). Like TSIS TIM, it will measure the total irradiance of the Sun with an uncertainty of
SPIE Conference Proceedings


Solar irradiance, cubesat, carbon nanotubes, total solar irradiance (TSI)


Harber, D. , Lehman, J. , Tomlin, N. , Yung, C. , White, M. , Castleman, Z. , Drake, G. , Van, S. , Farber, N. , Heurman, K. , Rutkowski, J. , Sims, A. , Sprunck, J. , Straatsma, C. , Wanamaker, I. , Zheng, W. , Kopp, G. , Pilewskie, P. and Stephens, M. (2019), Compact total irradiance monitor: Flight demonstration, SPIE Conference Proceedings, [online], (Accessed June 18, 2021)
Created August 30, 2019, Updated September 3, 2019